Transmission-line connector



Sept. 19, L BLONDER TRANSMISSION-LINE CONNECTOR Filed March 29, 1956 2 Sheets-Sheet 1 IN VEN TOR. \SAAC S BLON DER A T TORNEYS Sept. 19, 1961 l. s. BLONDER 3,001,169

TRANSMISSION-LINE. CONNECTOR Filed March 29, 1956 2 Sheets-Sheet 2 IN VEN TOR.

ISAAC S. BLONDER ATTORNEYS 3,001,169 TRANSMISSION-LINE CONNECTOR Isaac S. Blonder, 526 North Ave., Westfield, NJ. Filed Mar. 29, 1956, Ser. No. 574,906 9 Claims. (Cl. 339-477) The present invention relates to transmission-line connectors and, more particularly, to connectors adapted for use with coaxial transmission lines such as those employed in television and the like.

Audioand radio-frequency coaxial transmission lines are customarily interconnected by means of male and female coaxial-line connectors. While many types of such connectors have been devised, they, in general, may be classified in two broad categories. First, connectors that inherently require the use of solder and the like to establish mechanical and electrical connection from the outer and inner coaxial-line conductors to the corresponding outer and inner portions of the coaxial-line connector; and secondly, coaxial-line connectors of the solderless type which usually embody the crimping, wedging or other securing of the line conductors to the connector. Unfortunately, however, connectors of both types are subject to serious limitations. The soldering or securing must often be done blind," so that the effectiveness of the connection is not readily apparent. Not only do such conditions mitigate against the rapid application of connectors, but they impede visual checking and inspection. In addition, the connectors are not easily removable, once applied, After removal, moreover, they must be re-prepared before re-application to a cable, as by scraping and re-applying solder layers in the case of solder-type connectors, or by re-shaping the crimping, tapered or wedged areas in the case of the solderless conneetors.

An object of the present invention is to provide a new and improved transmission-line connector that shall not be subject to the above disadvantages and that, to the contrary, shall be readily adapted for rapid application and removal to and from a cable without preparatory treatment.

A further object is to provide such a novel connector that is particularly adapted for use with coaxial trans-.

mission lines.

Other and further objects will be explained hereinafter and will be more particularly pointed out in the appended claims.

In summary, the present invention embodies a tubular conductive connector member having first and second interiorly threaded portions of slightly different diameter that respectively grip the outer resilient jacket and an exposed portion of the outer conductor of the coaxial line. A third portion of the member contains a transverse wall having an aperture for receiving an exposed terminal portion of the inner conductor of the coaxial line. Preferred constructional details are presented hereinafter.

The invention will now be described in connection with the accompanying drawings FIG. 1 of which is a side elevation of a connector, constructed in accordance with a preferred embodiment of the invention with parts broken away to illustrate details of construction;

FIG. 2 is a perspective view of the connector of FIG. 1 prior to assembly with a coaxial transmission line;

FIGS. 3 to 6 are similar views, longitudinally sectionalized and illustrating successive steps in the assembly process;

FIG. 7 is an end elevation of the left-hand end of the connector of FIG. 6;

FIG. 8 is a view similar to FIG. 2 of a modified con- United States Patent nector prior to assembly with a coaxial transmission line and prior to connection to a cooperative outlet;

FIGS. 9 to 11 are views similar to FIGS. 3 to 6, but

illustrating successive steps in the assembly of the con tive lines 12l2 and 13-13 of FIG. 1l, looking in the direction of the arrows, and drawn upon an enlarged scale.

The transmission-line connector of the present invention is particularly adapted for use with the conventional type of coaxial line embodying an inner conductor 3 imbedded in an insulator 7, such as polystyrene, within a coaxially-disposed tubular outer conductor 5, as of copper braid. The outer conductor 5 is jacketed in a resilient insulating covering 1, usually of vinyl plastic and the like. Typical coaxial cables of this type are, for example, the RG59U cable and the RGllU cable. In the case of the former, the inner conductor 3 comprises a single wire, whereas, in the latter case, the inner conductor comprises several strands of wire. In all instances, however, whether a single wire or a plurality of wires are utilized, reference will be made hereinafter to an inner conductor. The cable is prepared for assembly with the connector of the present invention by stripping the free end of the coaxial line or cable to expose suecessive terminal portions of the inner conductor, as shown at 3 in FIG. 2; the inner insulation, as shown at 7, and the outer conductor, as shown at 5.

The transmission-line connector itself comprises a tubular conductive member 9 having a first interiorly threaded portion 11 at one end, shown as the right-hand end in FIGS. 3 to 6. Adjacent the threaded portion 11 is a second interiorly threaded portion 13 of slightly less diameter than the first portion 11, but having threads of preferably substantially the same pitch as those of the threaded portion 11 and threaded continuity therewith for reasons later explained. The inner diameter of the threaded portion 11 is made just slightly less than the outer diameter of the jacket 1 of the coaxial line, and the innerdiameter of the threaded portion 13 is made slightly less than the outer diameter of the outer conductor 5 for reasons that will also be hereinafter explained. Beyond the second portion 13 of the member 9, there is provided a third portion 15 containing interiorly a transverse insulating wall or disc 23. The wall or disc 23 may be provided peripherally with notches 25, FIG. 1, which may be engaged at crimped regions 27 in the space 21 between external flanges 17 and 19 of the third portion 15 of the tubular connector member 9, thus to secure the wall 23 within the third portion 15. Other techniques for mounting the wall 23 within the connector 9 may also be employed. The insulating wall 23 is apertured at 29, FIGS. 3 to 6, to receive the inner conductor 3 of the coaxial line, as later discussed. A hollow contact probe or pin 31 is mounted within the aperture 29 and extends axially along the cylindrical tubular member 9, to the left as shown in the drawings, beyond the left-hand end thereof, to contact the inner-conductor portion of a cooperative female connector, not shown, as later discussed. The probe 31 may be secured to the insulating wall 23 by swedging the right-hand end thereof, asat 33, the wall 23 thus serving as an insulating support for the probe 31 that electrically isolates the probe from the body of the member 9.

The prepared stripped portion of the coaxial line is inserted within the right-hand end of the cylindrical member 9, FIG. 4. The threaded region 11 will not engage the outer conductor 5 since it is of smaller diameter. When the line is sufiiciently inserted into the member 9 that the outer jacket 1 reaches the right-hand end of the member 9, however, relative rotation of the line and the member 9 will start threading the outer jacket 1 with the threads 11, as shown at 40, FIG. 5. The outer conductor will engage the threads 13 to thread the outer conductor 5, as at 42. If the threads 11 and 13 are of substantially the same pitch and substantially continuous, as before stated, the threading operation will continue smoothly without longitudinally separating the jacket 1 and the outer conductor 5. Ultimately, the terminal extension 3 of the inner conductor of the line will extend into the hollow probe 31, FIGS. 5 and 6. By this insertion process, therefore, the threaded portion 11 of the member 9 threadedly locks upon the jacket 1 and the terminal section 5 of the outer conductor of the coaxial line threadedly locks to the threads 13, thus both mechanically and electrically rigidly securing the outer conductor 5 to the conductive body of the member 9. The terminal portion of insulation 7 that is exposed between the outer conductor 5 and the terminal portion of the inner conductor 3 prevents any possible short-circuiting between the outer conductor 5 and the hollow probe 31 into which the inner conductor 3 has been inserted.

A resilient clamp or spring device 35 may be inserted within the hollow probe 31, FIGS. 6 and 7, resiliently to clamp, secure or press the conductor 3 against the inner wall of the probe or pin 31. To facilitate this operation, the free end of the probe 31 may be notched as at 38, FIGS. 1 and 2. In view of the notch 38, the resilient member 35 may be compressed and inserted within the probe 31 and any excess inner conductor trimmed, all from the outside, and without the necessity for special tools.

A conventional coaxial-line outer-connector sleeve 37 may initially be inserted over the jacket 1 of the coaxial line, as illustrated, before the assembly of the line within the member 9. The sleeve 37 is provided with interior threads 39 that, as shown in FIG. 6, may engage a thread ed flange 41, preferably disposed external to the portion 13 of the member 9. In order, moreover, to limit the degree of insertion of the probe 31 in a cooperating inner-conductor aperture of a female connector, not shown, a collar 45 is provided adjacent the left-hand face of the wall 23. To insure a similar limiting position for the member 9, one or more projections 43, FIGS. 1 and 2, may be provided along the periphery of the lefthand end of the member 9 of length corresponding substantially to the length of the collar 45.

It will thus be seen that a complete mechanical and electrical connection has been effected without the aid of solder, tapered or wedged constructions, and that may be readily inspected, repaired, or substituted merely by loosening the sleeve 37 and sliding it back along the jacket 1 to expose the connector 9. By threading the connector 9 on or oif the coaxial line and at the same time removing or inserting the clamp 35, rapid connections or disconnections may be effected. In addition, if it is desired to employ solder, this may be done in, for example, the region of the notch 38 or along the probe 31. If a solder connection is desired to the outer conductor 5, this may be eifected through an aperture 46 in the second portion 13 of the member 9.

While the connector of FIGS. 1 to 7 may have its dimensions scaled to fit coaxial lines of different dimensions, where relatively small-diameter coaxial lines are to be employed, such as the type RG-59/U, a somewhat simpler connector construction may be utilized. Such a simpler construction, moreover, is particularly adapted for use with coaxial outlets of the type shown in FIGS. 8 to 11, embodying a threaded outer-conductor sleeve 50 insulated at 52 from an inner-conductor recess 54. Thus, in FIGS. 8 to 11, the connector body 9' is shown provided with the first threaded portion .11 and the second threaded portion 13 of less diameter, for producing the threaded connections 40 and 42, FIG. 11, in the prevent short-circuiting with the terminal inner conduc tor portion 3 of the coaxial line when that terminal portion extends into the left-hand end of the portion 15, as illustrated in FIG. 11. The left-hand end portion 15' receives the outlet sleeve 50 with the inner conductor terminal portion 3 inserted within the outlet inner-conductor recess 54. By providing a slot 56 mar peripheral recess 58 in the end portion 15' that communicates with the interior of the end portion 15', so that a resilient wire spring 60 may be inserted in the recess 58, the connector 9' can be secured to the outlet 50 without threading thereupon. The member 60 is partially circular, hav ing a straight portion 62 that seats within the slot 56 and extends transversely of the end portion 15' to ride over and lock between the threads of the outlet sleeve 50, FIG. 13, as the connector 9' is merely pushed thereover. The resilient character of the member 60 provides for easy application to and removal from the outlet 50.

Further modifications will occur to those skilled in the art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A transmission-line connector for receiving and threadedly engaging a transmission line comprising a tubular conductive member having a first interiorly threaded portion adjacent one end of the member, a second interiorly threaded portion adjacent and of slightly less internal diameter than the internal diameter of the first portion, a third portion extending from the second portion to the other end of the memberand containing and supporting both a transverse wall provided with a conductor-receiving aperture, and a further tubular member extending beyond the said transverse wall and in-line with the said conductor-receiving aperture, the further tubular member being of outer diameter less than the inner diameter of the said third portion, and a resilient member engaging the further tubular member for maintaining in fixed position a conductor passed through the conductor-receiving aperture and into the said further tubular member.

2. A transmission-line connector as claimed in claim 1 and in which the said transverse wall is an insulating wall, the said further member is a hollow tubular contact probe, and the resilient member is disposed within-the said hollow probe to engage and apply pressure against the inner wall thereof.

3. A transmission-line connector as claimed in claim 1 and in which a slot is provided in at least part of the periphery of the said third portion for communicating with the interior thereof, and the resilient member comprises a spring secured within the slot for engaging the outer wall of the said further member.

4. A transmission-line connector as claimed in claim 3 and in which the said outer wall of the said further member is threaded and the spring is received within the threads thereof.

5. A transmission line connector for receiving and threadedly engaging a transmission line comprising a tubular conductive member having a first interiorly threaded portion adjacent one end of the member, a second interiorly threaded portion adjacent and of slightly less internal diameter than the internal diameter of the first portion, and a third portion extending from the second portion to the other end of the member and containing an insulating support secured therein, the support having an intermediate aperture within which is secured a hollow contact probe extending beyond the said other end of the member, notched at its free end and containing means for resiliently applying pressure against the inner wall of the hollow probe.

6. A transmission-line connector for receiving and threadedly engaging a transmission line comprising a tubular conductive member having a first interiorly threaded portion adjacent one end of the member, a second interiorly threaded portion adjacent and of slightly less internal diameter than the internal diameter of the first portion, a third portion extending from the second portion to the other end of the member and containing an apertured insulating support secured therein, and a contact probe extending from a collar adjacent the support outward beyond the said other end of the member and open at its free end, the contact probe and collar being supported by the walls of the said aperture of the said insulating support and in line therewith, and the said other end of the member having one or more outwardly extending projections of length corresponding substantially to the length of the said collar.

7. In a resiliently jacketed coaxial line having an end stripped to expose successive terminal portions of the inner conductor, the insulation thereabout and the outer conductor, a tubular conductive connector member for securing over the said end section of the coaxial line having a first interiorly threaded portion adjacent one end of the member for receiving and threadedly engaging the coaxial-line jacket adjacent the stripped end of the line, a second interiorly threaded portion adjacent and of slightly less internal diameter than the internal diameter of the first portion for receiving and threadedly engaging the exposed terminal portion of the outer conductor of the line, a third portion extending from the second portion to the other end of the member and provided externally with a pair of spaced flanges, an apertured insulating support secured with the third portion in the region corresponding to the space between the said pair of flanges, a hollow contact probe extending from the support axially beyond the said other end of the tubular member and open at its free end for receiving the exposed terminal portion of the inner conductor of the line, the contact probe being supported within the aperture of the insulating support, and a tubular clamp for insertion within the hollow probe for resiliently pressing the terminal portion of the inner conductor of the line against the inner wall of the hollow probe.

8. Apparatus as claimed in claim 7 and in which the member is provided with an externally threaded flange for receiving an interiorly threaded connector sleeve.

9. Apparatus as claimed in claim 8 and in which the hollow probe is provided with a collar adjacent the insulating support and one or more projections are provided at the said other end of the member of length corresponding substantially to the length of the said collar.

References Cited in the file of this patent UNITED STATES PATENTS 1,157,026 Meschenmoser Oct. 19, 1915 1,774,357 Cooper Aug. 26, 1930 2,022,669 Keefe Dec. 3, 1935 2,346,831 Drury Apr. 18, 1944 2,434,475 Sullivan Jan. 13, 1948 2,677,118 Stone Apr. 27, 1954 2,736,872 Heath Feb. 28, 1956 2,742,625 Bird et a1. Apr. 17, 1956 2,786,184 Alford Mar. 19, 1957 FOREIGN PATENTS 106,990 Australia Feb. 1, 1940 216,790 Switzerland Ian. 5, 1942 499,407 Great Britain Ian. 23, 1939 609,930 Great Britain Oct. 8, 1948 679,410 Great Britain Sept. 17, 1952 

